Toner-density calculating method, reflective optical sensor, and image forming apparatus

Abstract

In a reflective optical sensor in an image forming apparatus, an output from each N number of light-receiving elements (N≧3), obtained when M number of light-emitting elements (M≧3) included in a light-emitting unit emit detecting light, is separated into an amount of specularly reflected light and an amount of diffusely reflected light. The toner density of a pattern, which is formed on a supporting member in the image forming apparatus, is calculated based on a sum of the amounts of specularly reflected light and a sum of the amounts of diffusely reflected light.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2009-101691 filed in Japan on Apr. 20, 2009 and Japanese Patent Application No. 2009-213665 filed in Japan on Sep. 15, 2009. The present application incorporates by reference the entire contents of Japanese Patent Application No. 2008-238487 filed in Japan on Sep. 17, 2008.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a toner-density calculating method, a reflective optical sensor that is used in the toner-density calculating method, and an image forming apparatus. The image forming apparatus is provided, for example, in a multifunction product (MFP) that includes the reflective optical sensor and works as at least one of a copier, a printer, a facsimile machine, and a plotter.[0004]2. Description of the Related Art[0005]A variety of image forming apparatuses use...

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Benefits of technology

[0032]It is an object of the present invention to at least

Problems solved by technology

If the toner density is high, i.e., if the amount of the toner supplied to the electrostatic latent image is more than the necessary amount, a darker and difficult-to-see toner image will be formed.

However, it is difficult to always keep a relative position between the toner pattern and the reflective optical sensor in the main-direction the ideal state, due to various reasons.

If a portion of the spot falls in a region where there is no toner pattern because of the positional miss-match in the main-direction between the toner pattern and the reflective optical sensor, the reflected light received by the light-receiving unit represents wrong data, and therefore the calculated toner density is wrong.

Because the toner-density calculation is performed as the maintenance activity separated from the main activity, i.e., an image-forming process, the image forming operation cannot be performed during the toner-density calculation.

In other words, the larger the toner pattern is, the lower the operating efficiency of the image formation becomes.

Moreover, because a total amount of the toner in the toner container or the like is fixed, as an amount of the toner to be used for the toner pattern increases, an amount of the toner to be used for the main activity also increases, i.e., the image formation decreases disadvantageously.

In this manner, the conventional toner-density measuring methods have the two disadvantages, i.e., the low operating efficiency and the much toner-consumption amount for the toner pattern.

In other words, values of outputs (detection information) helpful to increase the sensitivity of the reflective optical sensor and the accuracy in the toner-density calculation are not properly used in the toner-density detection, resulting discarded uselessly.

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